1. Field of the Invention
The present invention relates to a liquid discharge head for discharging liquid and forming a flying liquid droplet thereby effecting recording, and formation of discharge opening (also called orifice) for discharging liquid. The present invention is applicable to an apparatus such as a printer for recording on a recording medium such as paper, yarn, fiber, fabrics, leather, metal, plastics, glass, timber, ceramics etc., a copying apparatus, a facsimile apparatus having communicating function, or a word processor having a printer unit, or an industrial recording apparatus combined in complex manner with various processing apparatus.
In the present invention, xe2x80x9crecordingxe2x80x9d means not only providing the recording medium with a meaningful image such as a character or graphics but also providing with a meaningless image such as a pattern.
2. Related Background Art
The ink jet recording apparatus, effecting recording by discharging recording liquid (ink) from the orifice of the liquid discharge head, is already known to be excellent in low noise and high speed recording.
Such ink jet recording method has been proposed in various systems, some of which are already commercialized and some are still under development for commercialization.
The liquid discharge head for such recording method is for example composed, as shown in FIGS. 6 and 7, of an orifice plate 40 having an orifice for discharging the liquid, a ceiling plate 400 for forming a liquid path 401 communicating with the orifice, and a substrate 100 constituting a part of the liquid path and provided with an energy generating element 101 (hereinafter called heater) for generating energy for ink discharge.
The orifice plate 40 is provided with a small orifice 41 for discharging ink, and the orifice 41 constitutes an important element governing the discharging performance of the liquid discharge head. The orifice plate 41 of the liquid discharge head 40 is required to be satisfactorily workable in order to form the small orifice, and to have satisfactory ink resistance as it is in direct contact with the ink.
For meeting these requirements, there has conventionally been employed a metal plate such as of SUS, Ni, Cr or Al, or a resinous film material easily and inexpensively available in a desired thickness such as of polyimide, polysulfone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide or polypropylene.
On the other hand, with the recent progress in the recording technology, there has been required recording with a higher speed and a higher definition, and, for this reason, the orifices 41 are being formed with a smaller size (orifice diameter) and with a higher density. As a result, there have been devised various methods for forming the orifice 41, and, in case of using the resinous film, the orifice is formed with a laser beam which is suitable for fine working. Also in case of employing a metal plate, the orifice 41 is formed for example by electroforming.
However, it is extremely difficult to adjoin the orifice plate 40 having a small orifice and the corresponding liquid path 401 without a gap to the neighboring orifice 41.
For this reason, there has been employed a method of adhering the resinous film for forming the orifice to the main body of the head and then forming the orifice with the laser beam as disclosed in the Japanese Patent Application Laid-open No. 2-187342, or of employing a dry film or the like for the orifice plate, pressing the dry film in a softened state by heating into the adhering face of the main body of the head thereby pressing the softened orifice plate into the liquid path and forming the orifice by a photolithographic process or with a laser beam, as disclosed in the Japanese Patent Application Laid-open No. 2-204048.
The orifice of the liquid discharge head preferably has so-called tapered shape in which the diameter gradually decreases from the liquid path side to the discharge opening side, but, if the orifice plate after formation of the orifice of such tapered shape is adhered by applying adhesive resin for example by transfer method, such adhesive resin may intrude into the orifice to very the tapered shape thereof, thereby resulting in a drawback such as fluctuation in the direction of discharge. Also a bubble inclusion caused by defective contact induces insufficient adhesion in the partition to the neighboring orifice, thus resulting in defective liquid discharge.
Consequently, there is also adopted a method of forming a step in the vicinity of the orifice, in order that the adhesive resin does not intrude into the liquid path and the orifice, as disclosed in the Japanese Patent Application Laid-open No. 5-330061.
Furthermore, in case of adhering the orifice plate having the orifice to the adhering face of the main body of the head, the positional aberration may take place by the contraction of the adhesive resin at the hardening thereof. Therefore, as disclosed in the Japanese Patent Application Laid-open No. 2-78560, there is also adopted a method of forming surface irregularities on the adhering face of the orifice plate, in order to prevent the influence caused by the contraction of the adhesive resin at the hardening.
Also the main body of the liquid discharge head, to be adhered to the above-mentioned orifice plate, can be prepared for example by the following method. On a silicon substrate, discharge energy generating elements are formed, and photosensitive resin for forming the liquid path walls is laminated thereon. Thereafter the photosensitive resin is patterned to form the desired liquid path walls. After the formation of the liquid path walls, a ceiling plate, composed for example of a glass plate, is laminated thereon to complete the liquid paths. Then the obtained laminated body is cut for example with a diamond blade to separate the liquid paths and to adjust the length thereof. Then the orifice plate is adhered for example an adhesive material in such a manner that the orifices communicate with the liquid paths to obtain the desired liquid discharge head. FIG. 39 is a perspective view showing a conventional example of the liquid discharge head and FIG. 40 is a plan view thereof.
In the liquid discharge head shown in FIGS. 39 and 40, liquid path walls 1301 and electrothermal converting elements 1303 serving as the discharge energy generating elements are formed on a silicon substrate 1309, and a ceiling plate 1310 composed for example of a silicon substrate is adhered thereon. The laminated body is cut off with a diamond blade for the purpose of adjusting the position of the liquid paths 1302, and an orifice plate 1307 is adhered with adhesive 1306 for example epoxy resin.
Also in such liquid discharge head, there has been a drawback that the adhesive employed for adhering the orifice plate enter and clog the liquid path. For this reason, there is adopted the method of forming a step in the vicinity of the orifice thereby preventing intrusion of the adhesive into the liquid and the orifice as disclosed in the Japanese Patent Application Laid-open No. 5-330061.
However, the above-described conventional configurations have been associated with the following drawbacks.
In pressing the softened resin into the liquid path at the adhering operation of the orifice plate to the main body of the head, the intruding amount of resin into the liquid path is difficult to control. As the orifices become smaller in diameter and higher in density, the resin intruding into the liquid path significantly influences the discharge performance, resulting in fluctuations of the discharge amount among the nozzles.
Also, with an increase in the density of the orifices and with the recovery operation of the orifice face surface, the distance between the orifices becomes shorter, and, if the step structure is formed in the vicinity of the orifices in order to prevent intrusion of the adhesive resin therein, the adhesive strength between the orifices is lowered thereby deteriorating the durability of the liquid discharge head.
Also, with an increase in the density of the orifices, with the use of various inks and with the recovery operation of the orifice face, the adhesive strength between the orifice plate and the main body of the head unless the grooved portion is adhered, thereby deteriorating the durability of the liquid discharge head.
Also in case the resin film is employed for the orifice plate, the laser beam is advantageous for fine working such as orifice formation. However, if the laser working is executed after the orifice plate is adhered, dust such as carbon powder generated by the laser ablation enters the nozzles, thereby resulting in clogging of the orifice or solid deposition on the heater, leading to the defective liquid discharge.
Also in the conventional configuration where the length of the liquid path is adjusted by cutting the adhesion face, to the orifice plate, of the main body of the head, there may result intrusion of cut power and dusts into the liquid path and chipping or cracking of the cut face. Also if the step structure is formed in the vicinity of the orifice, the adhesion strength between the orifices is lowered thereby deteriorating the durability of the liquid discharge head.
In consideration of the foregoing, an object of the present invention is to provide a liquid discharge head and a producing method therefor, capable of resolving the aforementioned drawbacks in the conventional configurations, preventing the intrusion of the adhesive material into the orifice and the trapping of bubble in the vicinity of the orifice, improving the adhesion strength between the orifice plate and the main body of the head, and preventing the intrusion of dusts, such as carbon powder generated by laser ablation, into the liquid path.
Another object of the present invention is to provide a liquid discharge head and a producing method therefor, capable, in adjusting the length of the liquid path by cutting the adhesion face of the head main body with the orifice plate, of preventing intrusion of dusts and chipping of the cut face at the cutting operation, thereby ensuring a high process yield and improved print quality.
The above-mentioned objects can be attained, according to the present invention, by a liquid discharge head including:
an orifice plate having plural discharge openings for discharging liquid droplets, and
a head main body provided with plural liquid paths for respectively communicating with the plural discharge openings, a liquid chamber for liquid supply to the plural liquid paths, a supply aperture for liquid supply to the liquid chamber, and plural energy generating elements provided corresponding to the plural liquid paths and adapted to generate energy for discharging the liquid droplet, and formed by adjoining the orifice plate with an adhesion face of the head main body on which the apertures of the liquid paths for communicating with the discharge openings of the orifice plate;
wherein the orifice plate comprises a recessed portion and a protruding portion on the adhesion face with the head main body, and the protruding portion has a shape corresponding to the cross-sectional shape of the liquid path and is provided the discharge opening therein, and the protruding portion or a part thereof is made to enter and to fit with the liquid path of the head main body and the adhesion face of said orifice plate is adjoined with the adhesion face of the head main body.
According to the present invention there is also provided a method for producing a liquid discharge head formed by adjoining an orifice plate having plural discharge openings for discharging liquid droplets, and an adhesion face of a head main body provided with plural liquid paths for respectively communicating with the plural discharge openings, the method comprising steps of:
forming, on an adhesion face of the orifice plate with the head main body, a recess portion and a protruding portion of a shape matching the cross-sectional shape of the liquid path; and
inserting and fitting the protruding portion of the orifice plate or a part thereof into the liquid path of the head main body, and adjoining the orifice plate with the head main body thereby forming the liquid discharge head.